// Copyright(c) 2019 ZVYAGIN.Alexander@gmail.com
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

#include <spdlog/details/null_mutex.h>
#include <spdlog/details/os.h>
#include <spdlog/details/synchronous_factory.h>
#include <spdlog/sinks/base_sink.h>

#include <array>
#ifndef SD_JOURNAL_SUPPRESS_LOCATION
#define SD_JOURNAL_SUPPRESS_LOCATION
#endif
#include <systemd/sd-journal.h>

namespace spdlog {
namespace sinks {

    /**
 * Sink that write to systemd journal using the `sd_journal_send()` library call.
 */
    template <typename Mutex> class systemd_sink : public base_sink<Mutex>
    {
    public:
        systemd_sink(std::string ident = "", bool enable_formatting = false)
            : ident_{std::move(ident)}, enable_formatting_{enable_formatting}, syslog_levels_{{/* spdlog::level::trace      */ LOG_DEBUG,
                                                                                               /* spdlog::level::debug      */ LOG_DEBUG,
                                                                                               /* spdlog::level::info       */ LOG_INFO,
                                                                                               /* spdlog::level::warn       */ LOG_WARNING,
                                                                                               /* spdlog::level::err        */ LOG_ERR,
                                                                                               /* spdlog::level::critical   */ LOG_CRIT,
                                                                                               /* spdlog::level::off        */ LOG_INFO}}
        {
        }

        ~systemd_sink() override {}

        systemd_sink(const systemd_sink&) = delete;
        systemd_sink& operator=(const systemd_sink&) = delete;

    protected:
        const std::string ident_;
        bool enable_formatting_ = false;
        using levels_array = std::array<int, 7>;
        levels_array syslog_levels_;

        void sink_it_(const details::log_msg& msg) override
        {
            int err;
            string_view_t payload;
            memory_buf_t formatted;
            if (enable_formatting_)
            {
                base_sink<Mutex>::formatter_->format(msg, formatted);
                payload = string_view_t(formatted.data(), formatted.size());
            }
            else
            {
                payload = msg.payload;
            }

            size_t length = payload.size();
            // limit to max int
            if (length > static_cast<size_t>(std::numeric_limits<int>::max()))
            {
                length = static_cast<size_t>(std::numeric_limits<int>::max());
            }

            const string_view_t syslog_identifier = ident_.empty() ? msg.logger_name : ident_;

            // Do not send source location if not available
            if (msg.source.empty())
            {
                // Note: function call inside '()' to avoid macro expansion
                err = (sd_journal_send)("MESSAGE=%.*s",
                                        static_cast<int>(length),
                                        payload.data(),
                                        "PRIORITY=%d",
                                        syslog_level(msg.level),
#ifndef SPDLOG_NO_THREAD_ID
                                        "TID=%zu",
                                        msg.thread_id,
#endif
                                        "SYSLOG_IDENTIFIER=%.*s",
                                        static_cast<int>(syslog_identifier.size()),
                                        syslog_identifier.data(),
                                        nullptr);
            }
            else
            {
                err = (sd_journal_send)("MESSAGE=%.*s",
                                        static_cast<int>(length),
                                        payload.data(),
                                        "PRIORITY=%d",
                                        syslog_level(msg.level),
#ifndef SPDLOG_NO_THREAD_ID
                                        "TID=%zu",
                                        msg.thread_id,
#endif
                                        "SYSLOG_IDENTIFIER=%.*s",
                                        static_cast<int>(syslog_identifier.size()),
                                        syslog_identifier.data(),
                                        "CODE_FILE=%s",
                                        msg.source.filename,
                                        "CODE_LINE=%d",
                                        msg.source.line,
                                        "CODE_FUNC=%s",
                                        msg.source.funcname,
                                        nullptr);
            }

            if (err)
            {
                throw_spdlog_ex("Failed writing to systemd", errno);
            }
        }

        int syslog_level(level::level_enum l) { return syslog_levels_.at(static_cast<levels_array::size_type>(l)); }

        void flush_() override {}
    };

    using systemd_sink_mt = systemd_sink<std::mutex>;
    using systemd_sink_st = systemd_sink<details::null_mutex>;
}  // namespace sinks

// Create and register a syslog logger
template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> systemd_logger_mt(const std::string& logger_name, const std::string& ident = "", bool enable_formatting = false)
{
    return Factory::template create<sinks::systemd_sink_mt>(logger_name, ident, enable_formatting);
}

template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> systemd_logger_st(const std::string& logger_name, const std::string& ident = "", bool enable_formatting = false)
{
    return Factory::template create<sinks::systemd_sink_st>(logger_name, ident, enable_formatting);
}
}  // namespace spdlog
